1. Field of the Invention
The invention relates to a thin integrated circuit card having an improved manually actuated switch.
The invention relates in particular to an integrated circuit card of the type having two external plates, a lower and an upper plate, separated by at least one intermediate plate, of the type in which the plates have electronic components connected to each other by conducting traces, and of the type containing at least one switch able to allow or prohibit passage of an electric current between two of its terminals that are connected to at least one of the traces.
Because new manufacturing techniques have been developed, it is now possible to obtain very small-sized electronic components that can be integrated into cards with a very small total thickness.
2. Description of the Related Art
French Patent Application No. 96.12661 has now proposed an integrated circuit card having both a chip with flush contacts and a circuit for producing sound signals that is connected to a sound transducer, the whole being contained in the total thickness of the card which does not exceed 0.8 mm, which is compatible with the widest-spread standard format for integrated circuit cards.
Such cards, provided with a sound signal producing circuit, can transmit coded information over a classic telephone line, such information serving for example for remote control of various types of apparatus.
This information is generally coded by a principle known in English as "dual tone modulation frequency (DTMF)."
However, the presence of such a circuit requires provision of a trigger switch designed to be actuated by the card user to cause coded signals to be transmitted.
According to the prior art, such switches are made in the form of a deformable dome provided on one of the external faces of the card, which the user must press in the thickness direction of the card to establish an electrical contact between the deformed dome and a conducting area provided opposite the dome on one of the faces of the card.
To trigger such a switch, the user must grip the card in its thickness direction, for example between the thumb and index finger, and he generally applies substantial force to the card which necessarily bends it, particular in the case of very thin cards.
Such bending, repeated regularly, can eventually damage some of the components of the card, which then becomes unusable.